David Letterman announced plans to retire next year on Thursday's Late Show.
The host, who has been on CBS since 1993, made the announcement to his studio audience at an afternoon taping.
"The man who (runs) this network, Leslie Moonves, he and I have had a relationship for years and years and years, and we have had this conversation in the past, and we agreed that we would work together on this circumstance and the timing of this circumstance," Letterman said. "And I phoned him just before the program, and I said 'Leslie, it's been great, you've been great, and the network has been great, but I'm retiring.'"
He added: "I just want to reiterate my thanks for the support from the network, all of the people who have worked here, all of the people in the theater, all the people on the staff, everybody at home, thank you very much. What this means now, is that Paul and I can be married."
"We don't have the timetable for this precisely down – I think it will be at least a year or so, but sometime in the not too distant future, 2015 for the love of God, in fact, Paul and I will be wrapping things up," he added.
Letterman, 66, has been a TV fixture for 32 years. He was the first host of NBC's Late Night, starting in 1992, but left when NBC passed him over for Jay Leno when Johnny Carson retired a decade later.